ULQ2801A

Overview

The ULQ2801A is an eight-channel NPN Darlington transistor array manufactured by STMicroelectronics. It integrates common emitters and internal suppression diodes for inductive load protection. Each channel supports a continuous collector current of 500 mA with a peak rating of 600 mA, while withstanding off-state voltages up to 50 V. The device includes a current-limiting resistor on each input, designed for general-purpose applications. It operates within an extended temperature range from -40 °C to +105 °C and is housed in an 18-lead plastic DIP package.

Feature Summary

• Integrates eight NPN Darlington transistors with common emitters
• Includes internal suppression diodes for inductive load protection
• Features built-in current-limiting resistors for general-purpose use
• Utilizes opposite input-output pinout to simplify board layout

Applications

• Driving inductive loads such as relays and solenoids
• General-purpose switching applications requiring high current gain
• Interfacing logic circuits with higher voltage or current devices

Procurement Notes

Verify the specific manufacturer datasheet revision before integration, as component specifications may evolve. Confirm that the 18-lead PDIP package aligns with your PCB footprint requirements. Ensure thermal management strategies account for the power dissipation characteristics at maximum load currents within the specified operating temperature range.

Selection Notes

Select the ULQ2801A when general-purpose switching is required without specific logic family matching constraints. Unlike other variants in the series, this version includes current-limiting resistors rather than fixed-value input resistors tailored for TTL or CMOS levels. Verify that the 50 V output voltage rating meets the system's inductive load requirements.

Part Context

The ULQ2801A belongs to the ULQ28xxA series of high-voltage, high-current switch arrays. This family provides multiple versions optimized for different logic families, including PMOS, TTL, and CMOS interfaces. All variants share the same physical package and core Darlington structure, differing primarily in input resistance configurations to facilitate direct interfacing with various digital control sources.

Replacement Considerations

The ULN2801A serves as a functional equivalent within the same product family. Both components share identical electrical characteristics, pinouts, and packaging. Substitution should be verified against the specific manufacturing datasheet to ensure compatibility with existing design parameters.